1. Field of the Invention
The present invention relates to an acoustic system provided in an acoustic space of, for example, home, vehicle compartment, movie theater, stage, concert hall or the like, the acoustic system comprising a sound input unit for inputting sound signals generated by a sound generator and at least a sound output unit, and more particularly to an acoustic system capable of contributing to improvement of appearance thereof and improvement of working efficiency and freedom of installation of its respective component units.
2. Description of the Related Art
Conventionally, for example, an acoustic system disclosed in Japanese Patent Application Laid-Open No. H7-288512 has been known as the acoustic system for use in acoustic space of, for example, home and vehicle compartment.
The acoustic system disclosed in the same publication comprises a wireless microphone transmitter which is a sound generator, a receiver for receiving a sound signal sent from the transmitter, an amplifier for amplifying a sound signal received by the same receiver at a determined amplification factor and a pair of speakers which are connected to the same amplifier through wire and convert a sound signal amplified by the amplifier to aerial vibration so as to produce sounds.
In such a system, the wireless microphone transmitter sends a sound signal picked up thereby to the receiver by radio and then, the amplifier amplifies the received sound signal. The amplified sound signal is sent to a pair of the speakers through wire and each of the speakers outputs a sound. Therefore, a person holding a wireless microphone transmitter can secure freedom of activity without being annoyed by handling the wire of a microphone.
However, because in the aforementioned conventional acoustic system, the wire still exists between the amplifier and a pair of the speakers, the wire needs to be placed around between the respective units to construct an acoustic system. Consequently, the wires placed around in this way damages the appearance of the acoustic system and the working efficiency and freedom of installation of the respective units. Therefore, there has been a problem to be solved in this point.
The present invention has been achieved to solve the above problem and therefore an object of the invention is to provide an acoustic system employing a radio transmitting medium as a transmitting medium for transmitting information containing sound signal between a sound input unit for inputting a sound signal generated in a sound generating source and at least a sound output unit instead of a conventionally used wire, thereby contributing to improvement of appearance and improvement of working efficiency and freedom of installation of respective related units.
To achieve the above object, according to an aspect of the present invention, there is provided an acoustic system comprising a sound input unit for inputting a sound signal generated in a sound generating source and at least one sound output unit for outputting sound based on the sound signal, wherein radio transmitting medium is employed as a transmitting medium for transmitting information containing the sound signal between the sound input unit and the at least one sound output unit.
The reason why a transmission object of the present invention is expressed as information including sound signal is that the transmission object includes not only the sound signal but also various control signals for command, control and the like and further, information concerning correction of a difference of time, which will be described later.
In the acoustic system of the present invention, a radio transmitting medium is employed as a transmitting medium for transmitting information containing sound signal between, for a sound input unit such as an amplifier and at least one sound output unit such as a speaker, instead of a conventionally used wire. As a result a necessity of placing wire around between respective units when establishing the acoustic system is eliminated, thereby contributing to improvement of appearance and improvement of working efficiency and freedom of installation of respective related units.
Here, an example of operation and effect which the present invention can exert will be described. That is, as a result of analysis of the frequency characteristic of man""s sense of hearing, it has been generally known that man""s sense of hearing has a directivity in middle and treble ranges while it has no directivity in bass range. This indicates that if an excellent sound field is intended to be formed, a squawker and a tweeter in charge of sound output in the middle and treble ranges are desired to be disposed to directly oppose the ears of a listener, while such a consideration is not necessary for a woofer in charge of sound output in bass range. When multiple speakers in charge of each sound range are disposed at each appropriate positions based on such a knowledge, the acoustic system of the present invention having a high working efficiency and freedom of installation of respective related units is expected to exert a very excellent effect.
In the meantime, in the acoustic system of the present invention, directivity of information transmitted between the respective units through radio transmitting medium is not restricted to any particular one. That is, for example, information containing sound signal may be transmitted in a single direction from the sound input unit to the at least one sound output unit or bidirectionally between the respective units.
According to a preferred embodiment of the present invention, part or all of the information is transmitted bidirectionally between the sound input unit and the at least one sound output unit.
According to this embodiment, part or all of the information containing sound signal is transmitted bidirectionally between the sound input unit and the at least one sound output unit. As a result, the information can be transmitted using a transmission style appropriate for the type of information to be transmitted. That is, for example, if the transmission object is only sound signal, one-direction transmission style is used, while if the transmission object includes not only the sound signal but also various control signal for command, control and the like and information concerning correction of a difference of time which will be described later, bidirectional transmission style is employed.
Major features and scope of application of the present invention have been described above. Disclosure of preferred embodiments of the present invention may be meaningful for clarifying an extension of the scope thereof.
In this viewpoint, according to a preferred embodiment of the present invention, the sound input unit comprises at least: an input interface for inputting a sound signal generated in the sound generating source; an encoder for digitizing the inputted sound signal; and a transmitting means for modulating the digitized sound signal and sending through the radio transmitting medium, and each sound output unit comprises at least: a receiving means for receiving a sound signal sent through the radio transmitting medium and demodulating the received sound signal; a decoder for decoding the demodulated sound signal; and an output interface for outputting a sound signal restored by the decoding.
According to this embodiment, first of all, a sound signal generated in a sound generating source is inputted into the sound input unit through the input interface. Then, the encoder digitizes the inputted sound signal and then, the transmitting means modulates the digitized sound signal and send it through the radio transmitting medium. On the other hand, in each sound output unit, a reception means thereof receives sound signal sent through the radio transmitting medium and demodulates the received sound signal. Then, the decoder decodes the demodulated sound signal. Consequently, a sound signal restored by the decoding is outputted through the output interface. By receiving the sound signal outputted through the output interface, the acoustic unit such as a speaker outputs sound.
As a result, this embodiment contributes not only to improvement of appearance but also improvement of working efficiency and freedom of installation of respective related units. Additionally, because the digital transmission method is employed, an acoustic system appropriate for such recent technological trend as prevalence of digital units can be realized.
If imagining a sound space to which the acoustic system of the present invention is applied, for example, home, vehicle compartment, move theater, stage, concert hall and the like can be exemplified. If the acoustic system of the present invention is applied to a relatively wide sound space and multiple sound output units are employed, a difference of time in arrival of sound signal between the respective sound output units becomes so large that it cannot be neglected, so that there may be generated such an event that makes listeners feel a sense of disharmony.
Thus, according to a preferred embodiment of the present invention, if multiple sound output units exist and a difference of time occurs between such multiple sound output units, this difference of time is corrected.
Because according to this embodiment, if multiple sound output units exist and there is generated a difference of time of the sound signal between the multiple sound output units, the difference of time is corrected, even if the difference of time between the respective sound output units becomes so large that it cannot be neglected, it is possible to avoid such an event that makes listeners feel a sense of disharmony.
Although the countermeasure for a difference of time generated between the multiple sound output units has been described above, various approaches for this correction of the difference of time can be considered.
As an example of various approaches, according to a preferred embodiment of the present invention, the information includes a block synchronous signal and a left/right synchronous signal and the difference of time is corrected based on both the synchronous signals.
According to this embodiment, the correction of the difference of time is carried out based on both the block synchronous signal and the left/right synchronous signal. Therefore, each of the multiple sound output units can cancel a difference of time and a difference of phase by only outputting sound synchronously with both the synchronous signals. Consequently, the difference of time can be corrected with such a simple method.
Further, according to a preferred embodiment of the present invention, correction of the difference of time is carried out based on a difference of time of the sound signal actually measured between the multiple sound output units.
Because according to this embodiment, the correction of the difference of time is carried out based on a difference of time actually measured of the sound signal between the multiple sound output units, a highly accurate correction of the difference of time can be carried out depending on an actual situation.
In the above described acoustic system, for example, if the transmission object is only sound signal, one-direction transmission style is used, while if the transmission object includes not only the sound signal but also various control signal for command, control and the like and information concerning correction of a difference of time, which will be described later, bidirectional transmission style is employed so that the information can be transmitted using a transmission style appropriate for the type of information to be transmitted. However, to transmit information including the sound signal between the sound input unit and the at least one sound output unit, it is important to prepare a system capable of identifying each unit.
Then, according to a preferred embodiment of the present invention, each of the sound input unit and the at least one sound output unit is provided with an address capable of identifying each unit.
According to this embodiment, such a system for specifying an address is arranged to enable respective units to identify each other. Therefore, when transmitting information between the sound input unit and the at least one sound output unit, if the transmitter is so constructed to specify addresses of a destination and the transmitter, the transmitter is capable of transmitting information by specifying a particular destination. Further, the receiver is capable of knowing from which transmitter information is received. Further, if speaking an example of application of such address specifying method, for example, assume that a sound signal is inputted to the sound input unit from multiple independent sound generating sources such as monophonic terminal, KARAOKE system, telephone or the like and then it is desired to distribute and output that sound signal to multiple sound output units. Then, by providing each of the multiple independent sound generating sources with an address capable of identifying each unit such that the sound generating source and sound output unit are connected to each other by specifying their addresses, multiple sound systems can be established. As a result, the aforementioned desired can be satisfied.
Here, the concept of xe2x80x9cproviding at least one sound output unit with an address capable of identifying itselfxe2x80x9d includes not only a case in which an address is given to each sound output unit but also is a concept including so-called group address in which an address is given to entirely multiple sound output units. If such group address concept is used, if sound volume, sound field balance or the like is desired to be set on the sound output unit according to an instruction from the sound input unit, not only various settings can be instructed to each particular unit, but also the various setting can be carried out in each sound output group at the same time so that each sound control unit belonging to the group is set to the same condition, by sending various setting signals to each sound output group such as right/left or front/rear.
Meanwhile, assuming that for example, four sound output units correspond to front left speaker, front right speaker, rear left speaker and rear right speaker, the xe2x80x9caddressxe2x80x9d used here is such a concept including a case in which the destination is specified by directly specifying individual locations such as front left. If such a concept is employed, the destination can be specified more easily corresponding to human sensitivity as compared to a case in which a determined address is specified from bit-column address allocated to each sound output unit.
Further, according to a preferred embodiment of the present invention, the at least one sound output unit actively changes a sound output function according to a command instruction sent from the sound input unit.
Because according to this embodiment, the at least one sound output unit actively changes its sound output function according to a command instruction sent from the sound input unit, for example if a command instruction for changing over the sound output function of the sound output unit dynamically is sent, the sound field can be changed dynamically at real time. Consequently, diversified applications of this effect can be expected, so that, for example, a novel acoustic effect can be produced in TV game, movie theater and the like.